THE BOTANY OF THE ROUTE. 
25 
valley between the Cascade and Coast ranges, but, like the yellow fir, stops at brackish water; 
and although a few are found down to the mouth of the Columbia, none grow along other rivers 
west of the Coast Range. It is a larger tree than the eastern white ash, and has all the 
elasticity and lightness for which that tree is so well known. 
The "Oregon dogwood" (Cornus Nuttallii) is still more strictly limited to the above 
valley, and seems to disappear north of Steilacoom. It much resembles that of the Atlantic 
States, but is of much larger size, in all its parts, and quite equal in toughness and strength. 
Its white flowers, sometimes six inches in breadth, ornament the forests in April. 
With a similar range, but extending quite to the Straits of Fuca, is the beautiful arbutus, 
(A. Menziesii,) often called laurel. Its smooth cinnamon-colored bark and shining evergreen 
leaves have almost a tropical appearance among the northern spruces, and it is, indeed, like 
the oak, one of the few southern trees which extend from southern California northward in the 
prairies. It grows almost luxuriantly on gravelly points and banks at the sound, but never 
west of the Coast range. It attains forty feet in height and two in diameter, and its wood is 
very strong and heavy, so that crooked pieces are used to make anchors by binding them 
around stones. 
Two, and perhaps more, species of poplar form the forest growth on the inundated river 
banks from an elevation of 5,000 feet down to tide-water. They are also found on all the 
rivers running from the Rocky mountains, and perhaps entirely across the continent. The 
latter is the "cotton-wood," (Populus monilifera.) The other, distinguished as "balsam" or 
"bitter" poplar, is peculiar to the western half of the continent, (P. angustifolia.) The wood 
of both is of little value, but they grow rapidly and are ornamental. The islands and low 
shores of the Columbia are covered with these trees, of larger size than I have ever seen them 
elsewhere. 
Another poplar, (P. tremuloides,) the "American aspen," common across the continent, 
grows on the high mountains and in small numbers about the lakes near Steilacoom, but not 
west of the Coast range. It is more abundant northward and east of the Cascades. Its wood 
is of little value, and rarely grows more than a foot in diameter, with a height of forty feet. 
Many species of willow grow along the rivers, but only two or three attain the size of trees. 
One, (Salix speciosa,) with very large and long leaves, seems mostly limited to the streams 
east of the Coast range. East of the Dalles this and a small hackberry (Celtis reticulata) are 
the only trees seen for hundreds of miles along the Columbia. 
The second (S. Scouleeiana) is most abundant west of the Coast range, and grows thirty feet 
high and one in diameter, but is of little value. Its leaves are large and oval, and its flowers 
among the first to appear, opening as early as February 20. 
The willows along river banks, by their thickly matted roots and stems, support the sandy 
soil, and accumulate it until it becomes high enough for other treea to grow on it. 
The wild cherry (Cerasus mollis) attains a height of thirty feet, and in appearance closely 
resembles the cultivated kinds, which may be advantageously grafted on it. Its wood is of 
little value, and its fruit small and bitter. 
The "Oregon crabapple" (Pyeus eivulaeis) grows sometimes twenty feet high and one in 
diameter, but usually forms low, tangled thickets, equal to the tropical mangroves in impene- 
trability. Its wood is hard and tough, used for wedges, &c., and its fruit, though small, is 
abundant and well flavored, ripening in October. At Astoria excellent apples have been 
produced by grafts on this tree. 
4 t 
